Assembly of a drive shaft with the cutting head hub of a submersible granulator

ABSTRACT

The invention relates to the assembly of a drive shaft with the cutting head hub of a submersible granulator. Said assembly comprises a connector hood which can be fixed to the drive shaft in such a way that it remains free to move. The connector hood is provided with threading for screwing the cutting head hub onto the drive shaft, said drive shaft being supported on a spherical extremity situated on the inside of the connector hood, and a cogged crown with inner-sided cogs is placed on the cutting head side of the drive shaft. The connector hood has inner-sided cogs which interlace with the cogs on the outer side of the cogged crown. The outer surface of each cog on the cogged crown is convex.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an assembly of a drive shaft with the cuttinghead hub of a submersible granulator according to the preamble of themain claim.

2. Description of Related Art

Self-aligning cutting head hubs for the assembly of the cutting head hubwith a drive shaft are known, whereby the self-aligning hub enables theknife blades of the cutting head disc to assume an optimal parallelarrangement with respect to the counteredges or to the extrusion-nozzleplates.

In the arrangement according to DE 196 42 389 A1, inserted into thecutting head disc is a hub that can adjust itself with respect to theplane of the cutting head disc, so that the possibility thereby existsof the plane of the cutting disc head assuming a slightly angularposition relative to the axis of the drive shaft.

A disadvantage of this known construction is the fact that the hub isintegrated into the cutting disc head, so that for each (possiblydifferently sized) cutting head the additional fitting of the costly huband of the components that enable its movement is necessary, that is tosay, the cutting head disc represents a relatively expensive, multi-partcomponent.

In order to avoid this disadvantage, in an arrangement (FIG. 3) that hasbecome generally known in practice, it is proposed that a connectionhood 25 be applied to the actual drive shaft 1, which hood displays atits outermost end an outer thread that can engage an inner threadprovided on the cutting head disc, so that thereby a simple fastening ofthe cutting head disc to the connection hood 25 is possible.

The connection hood 25 itself is supported in a pivoting manner andtransmits the contact pressure of the drive shaft 1, via a spherical end30 provided on the drive shaft 1, to a corresponding bearing on theinside of the connection hood 25. The drive shaft is driven in arotating manner and entrains the connection hood 25 in the direction ofrotation by means a groove-ball connection 27/28.

Due to this drive connection between the drive shaft and the connectionhood, this known construction possesses the disadvantage that largeforces must here be transmitted by the two balls. The processing of thebearing for the spherical ends in the connection hood 25 is expensive;in addition, at the spot where the greatest forces are transmitted,there exists for technical reasons a turned recess 29 where no force canbe transmitted, and over time a troublesome edge forms on the ball.

BRIEF SUMMARY OF THE INVENTION

The invention is based on the task of creating a self-aligningconnection between drive shaft and cutting head disc that is capable oftransmitting large forces without difficulty, these forces being bothlarge rotational forces for the driving of the cutting head disc andlarge forces of pressure for applying the cutting head disc to thecounteredge or to the extrusion-nozzle plate.

This task, on which the invention is based, is accomplished through theteaching of the main claim.

Advantageous configurations of the invention are explained in thedependent claims.

Expressed in other words, it is proposed that, in contrast to the priorart as it is known from DE 196 42 389 A1, the cutting head disc needdisplay merely an inner thread that engages an outer thread on theconnection hood, so that the cutting head disc, irrespective of the restof its design, need display only one thread for the attachment to thedrive shaft, which thread engages all of the outer threads on theconnection hood of the drive shaft. Thus, compared to this prior art, aconsiderable cost advantage is achieved.

In comparison to the prior art according to FIG. 3 that is known inpractice, the arrangement according to the invention has the advantagethat the force transmission between drive shaft and connection hood issubstantially improved, since now a plurality of cogs are engaged witheach other, yet in spite of this the desired pivoting movement of theconnection hood relative to the drive shaft and relative to the plane ofthe cutting head disc is possible.

The entrainment connection between drive shaft and connection hood isshifted very far toward the extreme end of the connection hood, wherebya better conduction of force among drive shaft, connection hood, andcutting head disc is achieved.

The structure according to the invention creates an advantageousshifting of the pivot point or of the center of rotation for the tippingmotion and of the point for the torque transmission in the directiontoward the cutting head disc.

In addition to the forming of the outer cog surface of each cog in aconvexly curved manner, according to the invention the cog flanks of thecogs can also be formed as convexly curved around an axis runningparallel to the longitudinal axis of the drive shaft, i.e. each cog isin itself broader at its middle than at the ends.

Through the provision of a pressure-transmission plate that isreplaceable and well-machinable in its non-attached state, a wearcomponent is created that can be easily replaced at any time upon theoccurrence of even the slightest wear. The ball that works inconjunction with the pressure-transmission plate can also consist ofcarbide, and since the ball is designed as a separate spherical body, ittoo is replaceable and can be quickly exchanged when wear occurs.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the following, an embodiment example of the invention is explainedwith the aid of the drawings. These show:

FIG. 1: the drive shaft with connection hood to be joined to the latter,shown pulled apart

FIG. 2: the drive shaft with connection hood in the assembled state

FIG. 3: the drive shaft with connection hood in a structure belonging tothe prior art.

DETAILED DESCRIPTION OF THE INVENTION

In the drawings, 1 indicates a drive shaft, which at its end 2 pointingtoward the cutting edge head to be attached (not shown in the drawing)displays outer cogs 3 that are formed by a cogged crown 4, whichdisplays individual cogs 7. The outer cog surface of each cog 7 is heredesigned in a convexly-curved manner, as can readily be seen from thedrawing, and in the represented embodiment example the cog flanks of thecogs 7 are also convexly curved around an axis running parallel to thelongitudinal axis of the drive shaft; in other words, each cog 7 is initself broader at its center than at the ends. The convex curving of theouter cog surfaces is essential, while the convex curving of the cogflank surfaces is not of such great significance and can be dispensedwith, for example for reasons relating to finishing technology.

The drive shaft 1 displays, at the end 2 pointed toward the cutting headdisc, a ball end 8; this ball end 8, as FIG. 2 clearly shows, is formedby a separate ball 12 that is arranged in a corresponding recess on theend of the drive shaft 1. In order to prevent a falling out of the ballwhen the apparatus is assembled, the ball can be cemented into itsreceptacle space, which is visible in FIG. 2.

Provided as a second separate component is a connection hood 5, which atits region coming into contact with the cutting head disc displays aconnection thread 9. In the interior this cutting head disc [sic]displays inner cogs 6 that can engage the cogged crown 4 when the latteris inserted into the region of the inner cogs.

The fastening of the connection hood 5 onto the drive shaft 1 takesplace with the aid of a connection ring 15, which can be fixed by meansof, for example, set screws 16, but which ring displays an inner openingthat is larger than the region of the drive shaft 1 that lies in theregion of this connection ring 15, as is clearly shown in FIG. 2. Bymeans of this structure, a relative pendulum movement between theconnection hood 5 and the drive shaft 1 is possible, which movementallows the plane of the cutting head disc to assume a slightly angularposition relative to the axis of the drive shaft, and an optimalparallel arrangement of the cutting head disc with respect to theextrusion-nozzle plate is ensured.

Finally, a pressure transmission plate 10 is provided, which plate canbe arranged inside the connection hood 5 and is produced as a separatecomponent. This pressure transmission plate displays a semi-sphericalrecess 11 that can come into contact with the outer face of the ball 12and is adapted to the shape and size of the ball. The ball 12 canconsist here of carbide and the pressure transmission plate 10 of amaterial that can work together with the ball 12 in an optimal manner.

From this, it is evident that when wear between the ball 12 and thepressure transmission plate 10 occurs, an easy replacement of bothcomponents is possible, without thereby requiring special interventionson the drive shaft 1 or the connection hood 5.

This occurrences of wear in the region between ball 12 and pressuretransmission plate 10 come about because the drive shaft 1 stresses theconnection hood 5 not only in a rotational manner, but also putspressure along the longitudinal axis of the latter, in order to pressthe connection hood 5 and the cutting head disc borne by the latter withthe appropriate pressure against the counteredge or the extrusion nozzleplate, as the case may be.

1. Assembly of a drive shaft with the cutting head hub of a submersiblegranulator, which assembly comprises a connection hood that isattachable in a pivoting manner to the drive shaft, which hood displaysat its outer end an outer threading for the cutting head hub to bescrewed on by means of a corresponding inner threading, the drive shaftabutting the inner side of the connection hood with a spherical end,wherein the spherical end of the drive shaft is designed as a ball,wherein a contact pressure is applied to said spherical end of the driveshaft in a direction along the axis of said drive shaft, wherein acogged crown having outer cogs is arranged at the cutting-head-side endof the drive shaft, wherein the connector hood has inner cogs thatengage the outer cogs of said cogged crown, and the outer surface ofeach cog of said cogged crown is convexly curved.
 2. Assembly accordingto claim 1, wherein the cog flanks of the cogs are curved around an axisthat runs parallel to the longitudinal axis of the drive shaft. 3.Assembly according to claim 1, wherein a pressure transmission plate isarranged on the inner side of the connection hood, which plate displaysat its center a semi-spherical recess adapted to the spherical end ofthe drive shaft.
 4. Assembly according claim 1, wherein the ball iscemented to the drive shaft.
 5. Assembly according to claim 1, whereinthe ball consists of carbide.